Electrical conductor



llg- 5, 1930. o. A. FREDERICKSON 1,772,436

ELECTRICAL CONDUCTOR Filed Sept. 50. 1927 ATTORNEY Patented Aug. 5, 1930 UNITED STATES 'PATENTI oFFicE OTTO A. FREDERICKSON, OF WETHERSI-EIELI), CONNECTICUT, ASSIGNOR TO THE WIRE- MOLD COMPANY, OFl HARTFORD, CONNECTICUT, A CORPORATION OF CONNECTICUT ELECTRICAL CONDUCTOR Application nla september 3o, 1927. serial No. 223,005.

'5 structed consist of a conductor Wire having a rubber jacket over Which is provided one or more layers of fibrous material, and it has been proposed heretofore `to treat the fibrous layers With various compounds to render them-moisturenproof and lire-repellant;

While the rubber jacket forms an excellent insulator for the conductor, it is not lire-repellant, and the rubber gradually deteriorates With the passage of time, becoming hard and inelastic. Furthermore, difficulty is sometimes experienced as a result of the fibrous covering slipping back off the rubber jacket to expose the latter.

Having in mind the foregoing the present invention relates to improvements in the construction of insulated conductors Whereby the life of the rubber jacket is increased and the same is afforded better protection from fire and mechanical injury than heretofore. These desired results are obtained by applying a coating of stearin pitch or other fire-repellant compound directly tothe outer surface of the rubber jacket, so that the pitch will form an air-tight coating'overthe rubber to prevent deterioration and hardening of the rubber due to oxidization and atlthe form of the invention.

same time protect the rubber jacket from fire.

The various features o`f the invention will be best understood from the following description when read in connection with the drawings which illustrate one good practical In the drawings y e Fig. 1 is a perspective view of an electric vin the drawings as having a conductor Wire 10 about-Which is provi-ded the usual rubber jacket 11, and i11` accordance with the present invention the rubber jacket 11 is provided With a protecting coating l2 of stearin pitch or other sticky flame-retarding compound that Will exclude air from the rubber jacket to reduce oxidization, and at the same time protect this jacket from fire.

The coating compound 12 should have the properties of remaining resilient or flexible 'permanently so that it Will not become hard and brittle upon the jacket as it ages, and it preferably should be sufiiciently sticky when applied to the rubber jacket to adhesively secure the covering 13, to be described, to the rubber jacket.

Stearin pitch forms an excellent protecting coating as it is fire-repellant to a high degree, due largely to its high melting point and its property of forming protecting blisters when exposed to fire, and it has the further property of remaining elastic or iiexible in all kinds of Weather. Furthermore, it retains its plastic, rubbery character over a long period of time and is suiiiciently adhesive to firmly adhere to the rubber jacket 1l and to the inner face of the protecting covering 13 izo/adhesively secure the covering 13 to the jacket 11.

The covering 13 is formed of fibrous material and may be braided, Woven, or other- Wise constructed, and is shown as a braid constructed of relatively large strands 14 of twisted paper which are interbraided with zlind secured in place by small strong strands It is desirable to render the protecting covering 13 water-proof so that the life of the covering and its insulating properties will not be reduced by the presence of moisture, it is also desirable to render the fibrous covering 13 fire-repellent to reduce the fire hazard. These objects are accomplished by applying to the outer surface ofthe coveringl a coating 16 of stearin pitch or other Water-proof and fire-repellent compound such as the compound 12 above described.

If stearin pitch is used. to form the outer coating 16 it will remain more or less sticky and thus make the treated conductor mea-n to handle, but this objection is completely overcome by applying to the sticky surface a thin j coating 17 of aran wax or the like to impart a slick linlsh to the covering as fully described and claimed in my Patent No. 1,635,829 granted July 12, 1927.

It will be seen from the foregoing that they coating of stearin pitch or the like applied to the rubber' jacket 11 in accordance with the present invention protects that jacket from fire and from the deteriorating action of the air While at the same time it serves to adbesively secure the covering 13 to the jacket 11 so that the covering will not slip back and expose the rubber. Furthermore, the presence of stearin pitch upon both the inner and outer face of the protecting sheath 13 increases the Waterproof and fire-repellant properties of the covered conductor.

What is claimed is:

An article of manufacture comprising, an electric conductor having a protecting jacket formed of a homogeneous compound of flexible 'insulating material kdeposited about the conductor and to the outer surface of which is applied a moisture-proofand firerepellant coating of stearin pitch, a covering of brous material applied over said pitch coatinfr and secured to the underlying jacket by the pitch, a second moisture-proof and fire-repellant coating of stearin pitch applied to the outer surface of said fibrous covering, and a lm of Wax-like material applied over said second coating.

ln testimonv whereof, I have signed my name to this specication.

OTTO A. FREDERICKSON. 

